Tool-centering pilot



March 17, 1931 AM/MA f wmf/wf JN/ Mw /w w N l' Il Patented Mar. 17, 1931 UNTE STATES PETER M. SCI-ILAUCI-I, OF DETROIT, MICHIGAN TOOL-CENTERING PILOT Reille 'for abandoned application Serial No. 119,038, led .Tune 28, 1926'. This application `filed March 5,

1930. Serial My invention relates to an improved pilot for centering and guiding a cutting tool in a boring, roaming, grinding, or other similar operation and this application is filed to take the place of my former application Serial Number 119,038, filed J une 28, 1926, which became abandoned April 27, 1928. It is particularly useful in connection vith tools such as valve seating tools or tools cf a similar character. v

My improved pilot is simple in construction; positive and accurate in its centering operation; adaptable for use with out-of-round, eccentric, or inaccurate openings or in openings which are oversize or undersize; and it is automatically adjustable to accommodate itself to a substantially wide range of variation in the size of openings.

A meritorious feature is the provision vof such a pilot having a three point bearing in the guide opening throughout substantially the length of the pilot. My improved construction comprises the minimum number of parts and is of a rugged, durable character. Other objects and advantages will more fully appear from the following specification, appended claims, and accompanying drawing, in which:

Fig. 1 is a fragmentary secti-onal view through the head of a cylinder showing my improved pilot in position in elevation therein,

Fig. 2 is a cross-sectional view taken on line 2 2 of Fig. 1,

Fig. 3 is an end view of the pilot member, and

Fig. l is a side elevation of the spring member.

In various tool operations it becomes necessary to center the tool relative to an opening which is to be rebored, reground, or otherwise finished, and it is essential also that the tool be guided therein in its centered position. This centering of the tool should be accomplished quickly and readily. The pilot which centers the tool should be of a simple rugged construction possessing a minimum number of parts so as to not get out of order easily and it should be capable of accurately and positively centering the tool relative to the aperture to be finished. The centering pilot should be of such a character as to be adaptable for operation in apertures of varying size and within openings which are eccentric, outof-round, or otherwise inaccurate. This adaptability of the centering pilot is made necessary by virtue ofthe very character of the work to be performed. My pilot construction answers the exacting requirements heretofore enumerated.

ln the drawing, let 10indicate the head of a cylinder having a valve opening 12 and a guide 111. A tool shank is indicated as 16. rThis shanlr has an intermediate tapered tool seat 18 upon which is mountedV a suitable cutting tool 20. Obviously this tool shank is adapted to receive tools varying in character and design. The shank is provided with a pilot extension 22 which is Vhere shown as being integral therewith.

rhis-pilot extension is of a. generally cylindrical form. lt has a flatted longitudinal face 24e t a point remote from the flatted face is a channel 26 which extends longitudinally of the pilot. I have shown this channel as disposed on the opposite sideA of the pilot from the flatted face. Mounted in the channel is a springmember 28. This spring member has an outwardly conveX face. lt is here shown as being circular in cross section. The spring is corrugated so that certain portions thereof project radially beyond the surface of the pilot and engage the guide wall as shown in Figs. 1 and 2.

ln the tool operation the pilot is inserted into the guide opening. The spring yields to permit the insertion of the pilot and centers the same within the opening with a three point bearing against the wall of the opening, the three bearing points being the spring and the two edges of the flatted face. These bearings extend throughout the length of the pilot and hold the same accurately in position. Gbviously the pilot is adapted to be received within openings which vary in size throughout a determined range. It is c pable of being received within an opening which is undersize or oversize a determined diameter. It is also adapted to be received within an opening which is eccentric, out-ofround, or otherwise inaccurate. It takes the place, therefore, of a multiplicity of pilots oi' definite ixed size and is automatically adjustable to meet the requirements of the particular tool operation necessary to be performed.

lrWhat l claim is:

l. The combination with a tool shank and a tool oi' an axially positioned pilot extending beyond the tool, said pilot being generally Cylindrical in forni and having a i'iatted longitudinally extending face and a longhi dinally extending channel positioned on the side opposite the latted face and a sprng extending lengthwise within said channel provided with an outwardly convex bearing portion extending beyond the surtace or the pilot.

2. The combinatie with a tool shank and a tool oi a pilot therefor, said pilot disposed axially with respect to the tool and extending therebej/ond and being ol generally Cylindrical shape and provided with a iiatted longitudinal tace and a longitudinally eX- tending channel remote 'from the face and a round corrugated spring disposed within said channel having portions extending radially beyond the surface oiA the pilot.

3. A tool shank having an intermediate part adapted to removably receive a tool and an axial pilot portion extending beyond such intermediate part, said pilot portion having' a liatted longitudinal face and a longitudinally extending channel remote from such latted face and provided with an outwardly convex yielding member situated within the channel and adapted to project outwardly therebeyond.

l. A tool shank having an intermediate tapered tool seat and a pilot extension positioned axially with respect to said seat, said pilot extension having a flat longitudinal lace and a longitudinally extending channel positioned on the side opposite the flat face and a linearly extending yielding member situated within said channel having portions normally projecting beyond the surface of the pilot adapted to be resistingly depressed within said channel.

ln testimony whereof, I, PETER M. SCHL/Yoon, sign this specification.

PETER M. SGHLAUCH. 

